Sheet transfer unit for printing presses



Jam. 6, 1965 H. E. PEYREBRUNE J 6 SHEET TRANSFER UNIT FOR PRINTING PRESSES Filed June 18, 1963 4 Sheets-Sheet 1 ATTORNEY$ Jan. 26, 1965 H, E. PEYREBRUNE 3,167,006

SHEET TRANSFER UNIT FOR PRINTING PRESSES Filed June 18, 1963 4 Sheets-Sheet 2 FIG.?)

INVENTOR.

HENRI E. PEYREBRUNE ATTORNEYS Jan. 26, 1965 H. E. PEYREBRUNE SHEET TRANSFER UNIT FOR PRINTING PRESSES 4 Sheets-Sheet 3 v,F'iled June 18, 1965 INVENTORf HENRI E. PEYREBRUNE MMxM ATTORNEYS Jan. 26, 1965 H. E. PEYREBRUNE SHEET TRANSFER UNIT FOR PRINTING PRESSES 4 Sheets-Sheet 4 Filed June 18, 1963 JNVENTOR.

HENRI E. PEYREBRUNE ATTORNEYS United States Patent 3,167,006 SHEET TRANSFER UNIT FUR PRINTING PRESEEES Henri E. Peyrehrune, River Forest, IlL, assignor to Miehle-Goss-Dexter, Incorporated, Chicago, Ill., a corporation of Delaware Filed June 18, 1963, Ser. No. 288,769 8 Claims. (ill. 101-483) The invention relates to sheet transfer mechanism for transferring printed sheets from one printing-press unit to the next adjacent unit in a tandem relation therewith and has reference, in particular, to a completely self-contained sheet transfer unit which will incorporate all the elements necessary to connect and drive associated printing units and to transfer sheets from the impression cylinder of one such unit to the impression cylinder of the next adjacent unit.

A multicolor sheet-fed printing press of the unit type, for example, requires means for accurately transporting sheets from one impression cylinder to the next. In the past, a plurality of transfer drums have generally been employed for the purpose of transferring sheets between units, and their diameter thus determines the distance be tween units. In the larger presses, either one or three transfer drums may be employed. However, since a minimum distance has been established for the necessary maintenance and convenience of the operator, a greater number of transfer drums are required in smaller presses. This is objectionable both from the standpoint of cost and complexity.

Accordingly, the present invention has for its main objective to provide a substitute for the transfer drums in the form of sheet transfer mechanism of the endless chain type which will have the following advantages:

Provide the shortest practical sheet travel path from one printing unit to the next;

Provide a low platform between units for the convenient location of the operator when working on the plate cylinder or on the inking mechanism;

Provide for the constant speed of the sheet during transfer, with no abrupt changes in velocity nor any whipping of the sheet, such as occurs in all presently known similar devices; and

Provide a smooth, uniformly curved sheet path with means for inducing floatation of the sheets bet-ween transfers.

Another and more specific objective of the invention resides in the provision of sheet transfer mechanism of the endless chain type, wherein efficient transfer operatioris are obtained with precise registration since the driving means provided by a gear train is so constructed and arranged that the member receiving the sheet controls the member which is transferring the sheet.

A further objective is to provide chain-transfer mechanism of the character described, which will incorporate circular control discs on the sprocket shafts for exerting pressure on adjustable stop studs on the sheet carriers whereby consistent radial positioning of the sheet carriers is obtained for the most efiicient and accurate transfer of the sheets to and from the impression cylinder and the sheet carriers of the said mechanism.

Another objective is to provide chain-transfer mechanism for transferring sheets between printing units in tandem wherein sheet travel will take place at cylinder surface speed and wherein the combination of multipurpose framing, track arrangement, and gear drive is capable of improved sheet transfer operations.

Another object of the invention is to provide chainconveyor mechanism for transferring sheets between printing-press units wherein the sheet carriers of the mechanism at each receiving and transfer end are completely disconnected from the chain conveyor andwhere- 3,1510% Patented Jan. 26, 1965 ice in control of the sheet carriers is taken over by revolving control arms respectively and which have interlocking engagement with the carriers for effecting movement of the carriers in turn through their path of travel during which sheet transfer operations take place.

With these and various other objectives and advantages in view, the invention may consist of certain novel features of construction and operation, as will be more fully described and particularly pointed out in the specification, drawings and claims appended here-to.

In the drawings which illustrate an embodiment of the device and wherein like reference characters are used to designate like parts:

FIGURE 1 is a side elevational view, parts being shown in section, of a series of individual transfer units constructed in accordance with the invention and arranged in tandem relation for co-acting operation;

FIGURE 2 is a horizontal sectional view, taken longitudinally approximately on line 2-2 of FIGURE 1, and showing the geared relation of the various elements;

FIGURE 3 is a top plan view showing one of the sheet carriers in operative relation with the chain conveyors;

FIGURE 4 is a vertical sectional view through the sheet carrier of FIGURE 3, approximately on line 4 -5, and showing sprocket structure and associated parts at one of the transfer ends of the conveyor mechanism.

FIGURE 5 is a transverse sectional view, taken substantially along line 5-5 of FIGURE 4;

FIGURE 6 is a sectional view taken substantially along the line 66 of FIGURE 4;

FIGURE 7 is a sectional view taken substantially along line '77 of FIGURE 4-; and

FIGURE 8 is a perspective view showing one of the chain yokes which are fixed to the sheet carriers.

In the drawings which disclose one embodiment of the invention, the numerals Ill, 11, and 12, FIGURE 1, indicate endless chain transfer units and which are disposed in tandem relation for transferring sheets from one press unit 13 to the next adjacent press unit 14 and then to unit 15. Each printing-press unit includes an impression cylinder such as 16 and 17 for units 14 and 15, respectively, and each cylinder is suitably journalled for rotation by a shaft 18.

The transfer units each include side frames 29, an arcuate connecting frame portion 21, and leg elements 22, and each such unit journals a receiver shaft and a transfer shaft at respective ends. For unit It), the transfer end includes shaft 23 journalled for rotation in side frames 20, and at this end, transfer of the sheet takes place to the impression cylinder 16. Following a printing operation by press unit 14, the sheet is transferred from cylinder 16 to the receiver end of unit 11. More particularly, sheet transfer takes place from the impression cylinder 16 to sheet gripper assemblies driven by sprocket structure fixed to the receiver shaft 24, which is also journalled by side frames Ztl. Unit 11 at its opposite end journals the transfer shaft 25 which co-acts with impression cylinder 17 and here again, following a print ing operation, the sheet is transferred from cylinder 17 to sheet-gripper assemblies at the receiver end of unit 12 as represented by the receiver shaft 2-6.

Since the chain conveyor mechanism and the sheet gripper assemblies for transferring the sheets is similar for all the units, it will be described for unit 11 only, with the understanding that the elements of unit 11 are duplicated for units lit and I2 and wherein they have the same mode of operation. At the receiving end of unit 11, the shaft 24 is provided with a pair of spaced sprockets 27 and 29, FIGURE 4, suitably fixed to said shaft 24 and over which pass the endless chains 28 and 39, respectively. At this receiver end of the unit, the side frames Zli support semicircular chain guides and track elements 31 and 32, secured to the respective side frames at 33. The chain guides and track elements 31 and 32 are disposed in encircling relation around the upper half of the sprockets 27 and 29 at respective sides. The arcuate track elements 34 and 37 constitute a continuation of the semi-circular elements and the said arcuate track elements are similarly located on respective sides of unit if. The track elements 35 and 36 are located in spaced relation to elements 34 and 37 so as to form a precise path, substantially continuous and armate in formation and of uniform width from the receiver end of the unit to the transfer end. It is thus necessary for the elements 34-35 to be concentric, or in other words, to have a common center, and the same can be said for the elements 3637.

At the transfer end of the unit ill the elements 34 and 37 are, in effect, joined by the semi-circular track elements 38, and which encircle, respectively, the upper half of the spaced sprockets 4d, fixed to transfer shaft 25. The

track elements 35 and 36 terminate at this transfer end similar to their termination at the receiver end and likewise the chains 23 and 3 each pass over a sprocket 49, whereby an endless path of arcuate shape is provided for the sheet carrier assemblies generally designated by numeral 50, FIGURE 3.

The chain conveyor mechanism of each transfer unit is provided with four sheet carriers and which are caused to travel around the endless path formed by the track elements by movement of the chain conveyors. However, the chain for the carriers are loose and the same do not exert any driving action on a printing press unit. The soie function of the endless chains is to pull the sheet carriers along the upper path formed by the track elements 3435 from the transfer end to the receiver end and then back to the transfer end on the lower set of track elements 3637.

In FIGURE 2, the gear train for driving the chain conveyor mechanisms and the press units is shown and wherein it will be observed that a relatively large gear is fixed to each receiver shaft. For example, the gear 41 is fixed to shaft 24 and a similar gear 43 is fixed to shaft 26. The intermediate gear 42, also of a diameter equal to that of gears 41 and 43, is journalled at respective ends of its shaft 44 by the frame 20 and by bracket '55. The driving action of the. gear train 4-1, 42 and d3 first drives the last transfer unit and then drives the preceding units so that driving action runs opposite to sheet travel. A second gear train drives only the members of the press units and includes a gear not shown on the cylinder shaft 1% of impression cylinder 16, which, in turn, meshes with a gear 4 6, of similar pitch diameter, on the transfer shaft 23 of unit it). The said gear on the cylinder shaft 18 also meshes with a gear 57 of the same pitch diameter on the receiver shaft 24 of the following transfer unit if. The shaft 13 of impression cylinder 17 is also provided with a gear and which meshes with similar pitch diameter gears 48 and 49 on the transfer and receiver shafts 25 and 26 respectively. The gear train 41, 42, and 43 accordingly drives the receiver shafts of the several transfer units and, as contemplated by the invention, the receiver shaft gears drive the impressioncylinder gears which, in turn, rive the transfer shaft gears. It will be understood from the fore oing that conditions of sheet transfer are identical at the transfer end and at the receiver end of the unit. In both cases, the member accepting the sheet is the controlling drive element.

The gripper assembly 543, FIGURE 3,'includes a gripper carrier having a base wail 51, side walls 52. and 53, and intermediate partitions The gripper shaft is rotatably mounted by the partitions 5'4.- and between the right hand end partition and wall 53, the actuating lever as is fixed to the extending and of the gripper shaft. The roller d7 is suitably mounted on one end of lever 55 for free rotation, FIGURE 7, whereas the opposite end of the lever is equipped with the adjustable stud 58 which engages the portion 59 of the carrier 5-3. The gripper rfl fingers 60 are fixed at spaced locations to the shaft 55 and the fingers co-act in a conventional manner with the gripper pads 61.

The gripper shaft 55 is tensioned in a direction to maintain the fingers 6t closed against the pads 61 by means of a torsion bar 62 which extends axially of the shaft. The torsion bar is anchored at its left end at as in end wall 52. The opposite end of the torsion bar is anchored to the extending end of the gripper shaft 55, the said extending end having the lever 56 secured thereto.

A bracket 65, U-shaped in top plan is fixed to the exterior surface of end wall 52 and a similar bracket 66 is fixed to end wall 53. Each bracket in turn provides a pair of studs such as 67 on which are rotatably mounted the carrier control rollers 68 and 70 respectively. The chain yokes 72 and 73 are also secured to the exterior of the brackets as by screws 74, the said chain yokes being shown in perspective in FIGURE 8. Each chain yoke is located centrally of its bracket between the control rollers at its end and the outer surface of each chain yoke is in effect bifurcated to form the spaced legs 75 and the groove 76 which groove extends in a top to bottom direction of the carrier. The'grooves '76 are provided by the chain yokes for the purpose of receiving the chain yoke rollers 77 and 78. The said rollers are fixed to and carried by the endless chains 23 and 30, respectively. When the chain yoke rollers are located in their respective grooves 76, it will be understood that the carrier assembly 5% is operatively connected to the chain conveyor mechanism and as the carrier is caused to travel by movement of the endless chains the control rollers 68 and '76 will have rolling movement on the track elements 35 and 37. The passage provided by the said track elements 3435 and 36-37 is such as to allow sufficient space for the control rollers so that they do not bind or freeze against the track elements.

However, when the carrier assembly is caused to travel around the sprockets at respective ends of the conveyor mechanism the invention contemplates that pressure will be applied to the carrier to force the control rollers thereof to ride on the inside surface of the semi-circular track elements 3 and 32. For this purpose, the sprockets 27 and 29 have associated therewith the circular control discs 86 and 81 and which may be integral with their sprocket and thus the discs have rotation as the sprockets and shaft rotate. The carriers 59 have a formation exteriorly of the bottom wall 51 providing 'angularly disposed bosses and which are adapted to receive the studs 7% which may be adjusted to the desired height by shims. Since each sheet carrier has spaced control rollers, namely, 68 and 70 at respective ends and also has the spaced studs '79 all as clearly illustrated in FIGURE 5, the action of the control discs 36 and 81 is to maintain a consistent radial positioning of the carriers as they travel around the sprocket structure. The control rollers are forced into contact with the inside surface of the semi-circular track elements as the carrier travels around the sprockets at both the transfer and receiving end of the chain mechanism. As a result, the transfer of the sheets to and from the impression cylinders and the sheet carriers takes place in an accurate and efiicient manner.

During sheet transfer and immediately preceding and following the same, the sheet carrier is disconnected from the endless chains since the chain yoke rollers 77 and 78 automatically pass out of the grooves '76 provided therefore in the chain yokes 72 and 73. This will be best understood by reference to FIGURE 5 wherein it will be seen that'in position A, the carrier is about to enter the path provided by the rotating control discs 80 and 81 and the semi-circular track eiernents 31 and 32. The chain yoke rollers 77 and'78 are located within the grooves 7s of the chain yokes fixed to the The carrier in position B has entered the transferzone register blocks. .84 and 86 progressively enter the slots and immediately blocks.

the approximate center of which is represented by the plane X--Y, since when the gripper fingers 60 pass through said plane sheet transfer takes place. The chain yoke rollers 77 and 73 have been automatically displaced from the grooves '76 due to the curvature of the track elements 31 and 32 and thelocation of the chain yokes 72 on the the chain yokes and the carrier is accordingly under the control of the chain mechanism. Although the carrier is disconnected from the endless chain mechanism during movement through the transfer zone, the drive to the carrier from the sprocket structure is maintained by means of revolving drive arms as best illustrated in FIGURE 6, which structure will now be described.

Only one such drive arm 82 is fixed by the securing screws 83 to the control disc 80 and said arm carries a roller 84 at its free outer end. A similar arm 85 is fixed to the control disc 81 by similar screws 83 and said arm carries a roller 86 at its outer end. Each roller is adapted to co-act with spaced register blocks 87 fixed to the carrier at respective ends. The register blocks are fixed by screws 88 to legs of the brackets 65 and 66 and thus the rigester blocks are located within the opening provided by. the bracket. Each register block is provided with a curved surface and the blocks are disposed to provide a slot of gradually decreasing width from the bottom to the top of the carrier as clearly evident from FIGURE 6. In position A, the carrier 50 is leaving the arcuate track elements 34-35 and is approaching the semi-circular chain guide and track elements 31 and 32 as described in connection with FIGURE 5. The arms 82 and $5 are about to enter the slots provided therefore by the register blocks 87. However, the rollers 84 and 85 have not as yet engaged the surfaces of the Between positions A and B, the rollers in advance of position B, the rollers contact the blocks and take over control of the carrier. At the time the arms take over control, it will be understood that the chain yoke rollers are about to pass out of the grooves 76 so that the drive to the carriers is gradually transferred from the endless chains to the drive arms and is thus maintained at all times.

In position B, the arms 82 and 85 are in full control with the rollers 84 and 86 having contact with the register This position B is immediately in advance of sheet transfer which takes place when the sheet grippers 60 pass through the planenrepresented byline X--Y. As previously described, the carrier is disconnected from the chain conveyor during travel of the carrier through the transfer Zone. However the drive to the carrier is maintained by the drive arms for the most eificient and accurate transfer of the sheets to and from the impression cylinders.

In position C of the FIGURE 6, the chain yoke rollers have again entered the grooves of the chain yokes, see

, FIGURE 5, and thus the chain conveyor mechanism is being supported in said telescoping relation therewith by the frame part 93 which is fixed at 94 to bracket 95. The bracket 95 is in turn fixed to and supported .by the cross bar 96. The gripper opening cam 96 has a high .carnrning portion 5'7 which is precisely positioned so fer zone.

.that the roller 57 of the actuating lever 56 will contact the same and ride over the portion to rock the lever and open the grippers at the proper time in the travel of the carrier.

As previously explained, the carriers 56 are disconnected during their travel through the transfer zone. Although disconnected from the chain mechanism, the carriers are still under the control of the sprocket structure being driven thereby through the instrumentality of the drive arms 82 and 85. In addition to proper radial positioning of the carrier as they travel around the sprocket structure, it is also necessary to obtain proper positioning in a lateral direction. This is. accomplished by structure shown in FIGURE 4 and which includes a pair of spaced studs 100 fixed to the bottom wall 51 of each carrier and which are provided with eccentric heads lltll. A lateral positioning block 102 is fixed to shaft 24 by screws such as 103. The blocks thus rotate bodily with the sprocket shaft and its position on the shaft is critical since the block 102 enters between the heads 101 at the proper time. The block is thus operative during travel through the transfer zone to accurately center the carrier and maintain lateral control of the same. The eccentric heads ltll are adjustable by rotation of the studs Ititl to assure the required spacing for receiving the block and for minor adjustment roller 57 is about to ride the incline of the cam portion 97 to thus effect an opening of the sheet grippers of the carrier. Immediately beyond the sheet transfer plane the grippers 60 will close on the sheet which, however, is still being held by the grippers of the impression cylinder. However, following such action, the impression cylinder grippers will release the sheet which is thereupon transferred to the carrier.

From the foregoing, it will be understood that the invention provides a sheet transfer unit which will transfer sheets between units of a printing press by conveyor chain mechanism and at the surface speed of the impression cylinder. Substantially semi-circular sheet paths are provided by the track elements and in combination therewith, the curved bottom wall of the transfer unit helps to induce natural flotation of the sheets between transrection and also in a closing direction tends to maintain the desired pressure contact as regards the teeth of the gear drives. The conventional register segments are required only to prevent loss of tooth contact between cam actions.

It will be" noted that when the carrier assembly 50 is separated from the chains during travel through the transfer zone, that it is controlled by three independent registering means which function to maintain each carrier assembly in precise relation with respect to the coacting impression cylinder. As will be evident from the foregoing description the radial register means includes the control discs and S1 and the coacting studs 79 which are on the carrier assemblies. The circumferential register means consists of the control arms S2 and which are accurately located on the shafts 24- and 25, and which coact with the curved surfaces of the register blocks 87.

-The dual register features as just described physically connect the carrier assemblies to the shafts and they take over the'drive of the carrier assemblies through the trans- The third registering means for the carrier assemblies includes the eccentric heads 101 on the carrier and the positioning block 102 on the shafts. The elements coact in a manner to control the lateral register position of the carrier assemblies as they travel through the transfer zone.

Having thus described a preferred embodiment of the invention, it is understood that the scope of protection is not to be limited by details of construction as various other forms of the device will be apparent to those skilled in the art without departing from the spirit of the invention or the scope of the claims.

I claim:

1. In a sheet transfer unit having a sheet receiving end and a transfer end, a receiver shaft at the receiving end, a transfer shaft at the transfer end, a pair of spaced sprockets on each shaft, a pair of endless chains passing over said sprockets and operatively connecting the shafts,

'a sheet carrier assembly extending transversely of said chains, means normally connecting the sheet carrier to said chains, said connecting means including a yoke member at each end of the carrier assembly and a chain yoke roller fixed to and extending transversely of the chains respectively, means associated with each pair of sprockets and having such operation on the endless chains and on the carrier assembly as to displace the chain yoke rollers from the yoke members thereby disconnecting the carrier assembly from the chains, said disconnection taking place as the carrier assembly travels through the transfer zone comprising part of its path around the sprockets, a pair of spaced register blocks fixed to the carrier assembly at each end, and drive arms rotating with the sprockets of each pair, said drive arms being operative to enter betweenthe spaced register blocksat the respective ends of the carrier assembly for engaging with and driving the carrier assembly through the transfer zone when the chain yoke rollers are disconnected from the yoke members.

2. In a sheet transfer unit having a sheet receiving end and a sheet transfer end, a receiver shaft at the receiving end and a transfer shaft at the transfer end, a pair of spaced sprockets on each shaft, a pair of endless chains passing over said sprockets and operatively connecting the said shafts, a sheet carrier assembly normally connected at its ends to said chains, a semi-circular chain guide and track element having encircling relation with each of the sprockets, a pair of spaced control rollers at each end of the carrier assembly, and control discs on each of the shafts in spaced concentric relation with the track elements and respectively alignedv therewith, whereby the control discs and the track elements form a semi-circular path at each end for the travel of the carrier assembly around the sprocket structure, the said rollers having rolling contact with thetrack elements and the carrier assembly having contact with the control discs.

3. A sheet transfer unit as defined by claim 2, additionally including adjustable studs fixed to the carrier assembly and adapted to have contact with the control discs, whereby the studs can be adjusted so that the discs apply pressure to the carrier to hold the control rollers in pressure contact with the track elements.

'4. In a sheet transfer unit having a sheet receiving end, a receiver shaft at said end, a pair of spaced sprockets on the shaft, a pair of endless chains passing over said sprockets, gear means for driving the receiver shaft, a sheet carrier assembly normally connected at its ends to saidchains, a semi-circular chain guide and track element having encircling relation with each of the sprockets,

control discs on the shaft in spaced concentric relation with the track elements, whereby the control discs and the track elements form a semi-circular path at each end for the travel of the carrier assembly around the sprocket structure, a pair of control rollers at each end of the carrier assembly spaced transversely thereof, said rollers being so disposed as to have rolling contact with the,

track elements, and a pair of studs at each end of the carrier assembly spaced transversely thereof, said studs being so disposed as to have contact with the control discs.

5 In a multi-color printing press, a sheet transfer unit for conveying sheets in register from the impression cylinder of one printing couple to the impression cylinder of the next printing couple comprising a receiver shaft at one end of said unit, a transfer shaft at the other end of the unit, a main drive gear on the receiver shaft, an intermediate idler gear adapted to transmit the drive from the main drive gear on one receiver shaft to the main drive gear on the next adjacent receiver shaft, a second drive gear on the receiver shaft, a corresponding gear on the impression cylinder shaft adapted to mesh with said second drive gear whereby the impression cylinder is driven by the receiver shaft, a gear on the transfer shaft adapted to mesh with the impression cylinder gear'whereby the transfer shaft is driven by the impression cylinder gear, gripper elements for receiving a sheet from the impression cylinder While said elements are controlled by the receiver shaft and for transferring said sheet to the impression cylinder of the next couple While said elements are controlled by the transfer shaft, the drive arrangement being such that the member receiving a sheet has direct and unrestricted control of the member from which the sheet is to be transferred.

6. In a multicolor printing press, a series of printing units arranged in tandem relation, a sheet carrying cylinder in each unit having grippers to control a sheet carried thereby, a series of sheet transfer units for conveying sheets seriatim from the cylinder of one printing unit to the cylinder of the next printing unit, said transfer units each having a receiver shaft at one end adjacent the cylinder of one printing unit and a transfer shaft at the other end adjacent the cylinder of the next printing unit, gripper means in each transfer unit for receiving a sheet from the grippers on the cylinder of said one printing unit and for transferring the sheet to the grippers on the cylinder 7 of the said next printing unit, means for connecting-the gripper means to the receiver shaft as said gripper means receive a sheet from the cylinder of said one unit, additional means for connecting the gripper means to the transfer shaft as said gripper means transfer a sheet to the cylinder of the said next unit, main drive means connected to each receiver shaft for driving the transfer units, other drive means for driving the cylinder of each printing unit from the adjacent receiver shaft, and additional drive means for driving the transfer shaft from the cylinder of the said next printing unit, whereby in the transfer of each sheet, the member receiving the sheet has direct and unrestricted control over the member which is transferring the sheet.

7. In a sheet transfer unit having a sheet receiving end and a sheet transfer end, a receiver shaftat thereceiving end, a transfer shaft at the transfer end, a pair of spaced sprockets on each shaft, a pair of endless chains passing over said sprockets and operatively connecting the said shafts, a sheet carrier assembly extending transversely of said chains, means normally connecting said sheet carrier to said chains, said connecting means including a yoke member at each end of the carrier assembly and a coacting chain yoke roller fixed to and extending transversely of the chains respectively, means associated with each pair of sprockets and having such operation on the endless chains and on the carrier assembly as to displace the chain yoke rollers froin the yoke members thereby disconnecting the carrier assembly from the chains, said disconnections taking place as the carrier assembly travels through the transfer zone comprising part of its path around the sprockets, drive arms rotating with the sprockets of each pair and operative to engage with and drive the carrier assembly through thetransfer zone when the chain yoke rollers are disconnected from the yoke members, additional means on the transfer and receiver shafts respectively, and adapted to rotate there- 2/ with, and coacting means on the carrier assembly, said means on the carrier assembly having interlocking coacting engagement with the said means on a shaft during travel of the carrier assembly through the transfer zone whereby to control the lateral positioning of the carrier assembly.

8. In a sheet transfer unit having a sheet receiving end and a sheet transfer end, a receiver shaft at the receiving end, a transfer shaft at the transfer end, a pair of spaced sprockets on each shaft, 2. pair of endless chains passing over said sprockets and operatively connecting the said shafts, a sheet carrier assembly normally connected at its ends to said chains, means associated with each pair of sprockets and operative to automatically disconnect the carrier assembly from the endless chains as the carrier assembly travels through the transfer zone 1% comprising part of its path around the sprockets, drive arms rotating with the sprockets of each pair and operative to engage with and drive the carrier assembly through the transfer zone when the carrier assembly is disconnected from the endless chains, a lateral positioning block on the transfer and receiver shafts, respectively, and adapted to rotate therewith, a pair of eccentric heads on the carrier assembly and spaced to receive a positioning block, said positioning block having a location on said shafts whereby the block is located between the eccentric heads as the carrier assembly travels through the transfer zone.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN A SHEET TRANSFER UNIT HAVING A SHEET RECEIVING END AND A TRANSFER END, A RECEIVER SHAFT AT THE RECEIVING END, A TRANSFER SHAFT AT THE TRANSFER END, A PAIR OF SPACED SPROCKETS ON EACH SHAFT, A PAIR OF ENDLESS CHAINS PASSING OVER SAID SPROCKETS AND OPERATIVELY CONNECTING THE SHAFTS, A SHEET CARRIER ASSEMBLY EXTENDING TRANSVERSELY OF SAID CHAINS, MEANS NORMALLY CONNECTING THE SHEET CARRIER TO SAID CHAINS, SAID CONNECTING MEANS INCLUDING A YOKE MEMBER AT EACH END OF THE CARRIER ASSEMBLY AND A CHAIN YOKE ROLLER FIXED TO AND EXTENDING TRANSVERSELY OF THE CHAINS RESPECTIVELY, MEANS ASSOCIATED WITH EACH PAIR OF SPROCKETS AND HAVING SUCH OPERATION ON THE ENDLESS CHAINS AND ON THE CARRIER ASSEMBLY AS TO DISPLACE THE CHAIN YOKE ROLL- 